Europe’s Challenge Is Decline, Not Trump

The greatest mistake Europeans can make is to believe that their biggest problem is Donald Trump.

To be fair, it’s an easy error to make. In the long annals of American diplomacy, there’s no previous instance of an American president treating close allies with anything approaching the Trumpian mix of critique and contempt.

But it’s not only Mr. Trump and his supporters whose attitudes should worry Europe. Some of Europe’s closest friends are also increasingly discouraged.